What is a colonoscopy?

Colonoscopy is a diagnostic procedure that allows the doctor to examine the entire length of the large intestine. Colonoscopy can assist in identifying problems with the colon, such as early signs of cancer, inflamed tissue, ulcers, and bleeding. Colonoscopy is also used to screen for colorectal cancer, the second leading cause of cancer-related deaths in the U.S. and the third most common cancer in men and women, excluding skin cancers.

How is the procedure performed?

An endoscope, which is a long, flexible, lighted tube (also called a colonoscope), is inserted through the rectum into the colon. In addition to allowing visualization of the internal colon, the colonoscope enables the doctor to irrigate, suction, inject air, and access the bowel with surgical instruments. During a colonoscopy, the doctor may remove tissue and/or polyps for further examination and possibly treat any problems that are discovered. A colonoscopy is typically an outpatient procedure.

Reasons for the procedure

A colonoscopy is the most effective method of detecting cancer in the early stage. Medical experts estimate that early screenings save thousands of lives each year. A colonoscopy may also, be used to examine colon polyps, tumors, ulceration, inflammation, diverticula (pouches), strictures (narrowing), and foreign objects within the colon. It may also be used to determine the cause of unexplained chronic diarrhea or gastrointestinal bleeding or to evaluate the colon after cancer treatment.

There may be other reasons for your doctor to recommend a colonoscopy.

Before the procedure

During your pre-procedure evaluation, the doctor will explain the procedure to you and offer you the opportunity to ask any questions.

You will be asked to fast for eight hours before the procedure, generally after midnight. You may be given additional instructions about a special diet for one to two days prior to the procedure.

Your doctor will instruct you about specific ways to prepare your bowel for the test. You may be asked to take a laxative, an enema, a rectal laxative suppository, and/or drink a special fluid that helps prepare your bowel.